. . . "For the manufacture of microelectronic substrates, e.g., the manufacture of silicon dioxide wafers, suitable etchants include a gas etchant, e.g. a chlorine or fluorine-based etchant such a CF4 or CF4/CHF3 etchant applied as a plasma stream, in accordance with known techniques. [0030] Carbon-dioxide cleaning drying compositions used to carry out the present invention typically comprise: [0031] (a)" .